SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China.
School of Environment, South China Normal University, University Town, Guangzhou 510006, China.
Molecules. 2020 Jul 10;25(14):3167. doi: 10.3390/molecules25143167.
Soil contamination by heavy metals threatens the quality of agricultural products and human health, so it is necessary to choose certain economic and effective remediation techniques to control the continuous deterioration of land quality. This paper is intended to present an overview on the application of biochar as an addition to the remediation of heavy-metal-contaminated soil, in terms of its preparation technologies and performance characteristics, remediation mechanisms and effects, and impacts on heavy metal bioavailability. Biochar is a carbon-neutral or carbon-negative product produced by the thermochemical transformation of plant- and animal-based biomass. Biochar shows numerous advantages in increasing soil pH value and organic carbon content, improving soil water-holding capacity, reducing the available fraction of heavy metals, increasing agricultural crop yield and inhibiting the uptake and accumulation of heavy metals. Different conditions, such as biomass type, pyrolysis temperature, heating rate and residence time are the pivotal factors governing the performance characteristics of biochar. Affected by the pH value and dissolved organic carbon and ash content of biochar, the interaction mechanisms between biochar and heavy metals mainly includes complexation, reduction, cation exchange, electrostatic attraction and precipitation. Finally, the potential risks of in-situ remediation strategy of biochar are expounded upon, which provides the directions for future research to ensure the safe production and sustainable utilization of biochar.
土壤重金属污染威胁农产品质量和人类健康，因此有必要选择某些经济有效的修复技术来控制土地质量的持续恶化。本文旨在综述生物炭作为一种添加物在修复重金属污染土壤方面的应用，从其制备技术和性能特点、修复机制和效果以及对重金属生物可利用性的影响等方面进行介绍。生物炭是一种由植物和动物基生物质经热化学转化而产生的碳中性或碳负性产物。生物炭在提高土壤 pH 值和有机碳含量、改善土壤持水能力、降低重金属有效态含量、提高农作物产量和抑制重金属吸收和积累方面表现出许多优势。生物质类型、热解温度、升温速率和停留时间等不同条件是控制生物炭性能特点的关键因素。受生物炭 pH 值、溶解有机碳和灰分含量的影响，生物炭与重金属之间的相互作用机制主要包括络合、还原、阳离子交换、静电吸引和沉淀。最后，阐述了生物炭原位修复策略的潜在风险，为未来的研究提供了方向，以确保生物炭的安全生产和可持续利用。
